| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical film causing no leak of light as a protective film for a polarizing film, having high fracture strength even when the film is stretched by large magnification, and useful for a wide wavelength region as a quarter wavelength phase plate, and to provide a method for manufacturing the film. <P>SOLUTION: The film is obtained by melting and extruding an alicyclic structure-containing polymer containing 55 to 90 wt.% of a repeating unit having a bicyclo [3, 3, 0] octane structure, having 25,000 to 50,000 weight average molecular weight and 1.2 to 3.5 molecular weight distribution. When the thickness of the obtained film is measured at 100 points along each of the extruding direction and the direction perpendicular to that with 5 cm interval and 20 cm interval, respectively, the arithmetic averages AX and AY and the maximum absolute values Xmax and Ymax of the difference between each measured thickness and the averages are obtained. The proportion X(%) of Xmax to AX and the proportion Y(%) of Ymax to AY satisfy the relation of (1): X≤5 and Y≤5 or (2): X≤8 and Y≤8 and |X-Y|/ä(X+Y)/2}≤0.35. <P>COPYRIGHT: (C)2003,JPO |
